Treatment of lubricating oils

ABSTRACT

The viscosity index of a lubricating oil is improved by contacting the oil at elevated temperature and pressure with a catalyst having hydrogenation activity in the presence of hydrogen and in the presence of carbon monoxide.

United States Patent 1191 Mead et al.

[ TREATMENT OF LUBRICATING OILS [75] Inventors: Theodore C. Mead; Richard L.

Coleman, both of Port Arthur; Billy H. Cummins; William B. Ashton, both of Nederland, all of Tex.

[73] Assignee: Texaco Inc., New York, NY.

[22] Filed: Apr. 25, 1973 [2]] App]. No.: 354,276

[52] US. Cl 208/1, 208/18, 208/112,

252/455 Z, 252/465 [51] Int. Cl ClOg 37/10, COlb 33/28 [58] Field of Search 208/l l1, I8, 112

[56] References Cited UNITED STATES PATENTS 3.531396 9/1970 Messing et a]. 208/] ll Primary E\'zm1iner-Delbert E. Gantz Assistant Examiner-G. E. Schmitkons Attorney, Agent, or Firm--T. H. Whaley; C. G. Ries [57] ABSTRACT The viscosity index of a lubricating oil is improved by contacting the oil at elevated temperature and pressure with a catalyst having hydrogenation activity in the presence of hydrogen and in the presence of carbon monoxide.

11 Claims, No Drawings TREATMENT OF LUBRICATING OILS This invention relates to a method for improving the properties of lubricating oils. More particularly, it is concerned with the production of lubricating oils of improved viscosity index by contacting a lubricating oil fraction with a hydrogenation catalyst in the presence of hydrogen containing a minor amount of carbon monoxide.

The hydrogenation of lubricating oils to improve various characteristics is well known in the art. There are generally speaking, three major types of reactions involved in the hydrogenation of lubricating oils. These reactions depend to a considerable extent on the type of catalyst and the reaction conditions of temperature, pressure and space velocity. Hydrocracking is the most severe of the three types and usually is practiced on the heavier lube oil fractions such as those having a major portion of the fraction boiling above about 1,000F. Hydrocracking effects a considerable amount of rupture of carbon to carbon bonds which results in an over-all reduction in the molecular weight of the lubricating oil and produces a considerable amount, depending on the severity of the treatment, of materials boiling below about 600F. The product generally has an improved viscosity index but a considerable loss in yield is sustained.

A less severe type of hydrogenation is generally referred to as hydrotreating or hydrofining. Ordinarily in this type of reaction the catalyst has little if any cracking activity but a significant amount of molecular rearrangement occurs although the principal purpose is to saturate aromatics and convert organically combined sulfur and nitrogen to hydrogen sulfide and ammonia. The reactions are usually sufficiently severe to produce some low boiling material.

The least severe of the hydrogenation reactions is usually called hydrofinishing and its general purpose is to effect a slight reduction in the sulfur and nitrogen content of the charge material and to remove color bodies from the oil. Ordinarily in hydrofinishing there is little change in the over-all boiling range of the lube oil fraction feed and accordingly the yields of lube oil from this hydrogen treatment is generally within the range of about 90-100 percent. Hydrofinishing also has substantially no effect on the viscosity index of the charge.

While hydrogenation under severe conditions has been used to improve the viscosity index of a lubricating oil fraction, ordinarily the yields are undesirably low because in order to improve the viscosity index a reasonable amount, a sizeable portion of the feed is converted to low boiling oils thereby making the process uneconomical.

It is an object of this invention to improve the viscosity index of lube oil fractions. Another object is to produce lubricating oil fractions of improved viscosity index using conditions less severe than those necessary in the prior art to effect the same results. These and other objects will be obvious to those skilled in the art from the following disclosure.

According to our invention, lubricating oils of improved viscosity index are prepared by contacting a lubricating oil fraction with a halogen-free hydrogenation catalyst in the presence of hydrogen containing a minor amount of carbon monoxide.

The lubricating oil fractions used in the process of and may comprise waxy distillates, deresined, decarbonized or deasphalted residual stocks, naphthene base oils, hydrocracked residuaand the like.

The reaction conditions in the hydrogenation zone include temperatures between about 550 and 850F., a preferred range being 600-800F. Suitable pressures include a range of about 500-2,000 psig. total pressure preferably 800l,500 psig. The lube oil charge stock may be introduced into the reaction zone at a space velocity of between about 0.1 and 5.0 volumes of oil per volume of catalyst per hour, a preferred range being between 0.3 and 2.0 v/v/hr. Hydrogen may be introduced into the reaction zone at a rate between about 500 and 10,000 standard cubic feet per barrel of charge, a preferred range being from 1,000 to 7,500 scfb.

It will be appreciated by those skilled in the art that the specific reaction conditions are selected from the above ranges to effect the desired result. For example, a low temperature such as 600F. coupled with a high space velocity such as 5 would result in a mild hydrofinishing reaction and would not have the desired effect. Similarly a low space velocity such as 0.1 coupled with a high temperature of 850F. would result in undesirable overcracking. However, a low space velocity combined with a low temperature within the above defined ranges would be satisfactory. Additionally the conditions will vary from one charge stock to another but one skilled in the art should have no difficulty in selecting the specific reaction conditions to fit the particular circumstances.

The hydrogen need not be pure. Satisfactory results may be obtained using hydrogen having a purity as low as 65 per cent. Suitable sources of hydrogen are catalytic reformer by-product hydrogen, electrolytic hydrogen and hydrogen produced by the partial oxidation of a hydrocarbonaceous material followed by shift conversion and CO removal.

The carbon monoxide may be introduced into the hydrogenation zone at a rate between about 0.01 and 10.0 mol per cent of the pressuring gas which is referred to herein as hydrogen. A preferred range is between 0.1 and 1.0 mol percent. Suitably, the hydrogen and carbon monoxide are introducedas a mixture.

The catalysts used in the process of our invention are composed of a hydrogenating component on a support. Suitable hydrogenating components comprise Group VIII metals such as the noble metals, e.g., platinum or palladium or iron group metals, e.g., cobalt and nickel and the compounds thereof. Optionally there may also be included in the hydrogenating component a' Group VI metal such as molybdenum or tungsten or compounds thereof. When the hydrogenating component is composed of a noble metalit may be present in the catalyst in an amount between about 0.1 and 5 percent by weight of the catalyst composite preferably between about 0.2 and 2 wt. percent. When thehydrogenating component is an iron group metal it may be present in an amount between about 1 and 10 percent by weight of the catalyst composite preferably between 2 and 8 percent. The Group VI metal used in conjunction with the Group VIII metal may suitably amount to between about 5 and 35 percent by weight of the composite, a preferred range being between 8 and 25 percent. The hydrogenating components may be present as the metal or metal oxide or sulfide.

Suitable catalyst supports comprise refractory inorganic amorphous oxides such as alumina, silica, magnesia, zirconia, titania and the like and mixtures thereof. Preferably the catalyst support comprises a mixture of The following examples are given for illustrative purposes only.

EXAMPLE I the catalytic hydrogenations are run in such a manner as to manufacture a product of predetermined quality,

higher yields may be obtained by means of the use of.

small amounts of carbon monoxide in the hydrogen.

silica and alumina with the alumina being present in an 5 This mp e Shows the ff of Carbon monoxide amount ranging hem/c6350 and 99 petrcem by Weight on the hydrocracking response of a dewaxed paraffin PP F y l include crystamfle in distillate using a nickel molybdenum on alumina cata- Caflomled hydrogen form amoummg between lyst. The hydrogenating compound in this instance is in abGut O and 50 W Pement of the pp Suitable 9' the oxide form. The charge is a dewaxed paraffin distillites are those obtained by the removal of alkali metal 10 late having kinematic viscosity at 1 f 7 5 ions from naturally Occurring or synthetic Zeolites centistokes and at 2 lOF. 12.10 centistokes. The vislng P openings of 6-13A u as faulasite and cosity index of the charge is 49. The charge is hydrolite Y and the like. Preferably the zeolite will have an cracked by being passed over a catalyst containing 3.5 alkali metal content of less than about 2.0 wt. percent. percent nickel and 18.5 percent molybdenum on alu- The catalyst should also be free of halogen. mina. Six runs are made, three at a temperature of The catalyst, in particulate form, may be used as a 750F. and three at a temperature of 825F., one run slurry, a moving bed or a fixed bed. Preferably the reacat each temperature being free from carbon monoxide, tion is carried out by passing the reactants through a one using hydrogen containing 0.5 mol percent CO and fixed bed of catalyst pellets. Reactant flow may be upone using hydrogen containing 5.0 mol percent CO. ward or downward through the bed or the gasmay flow Data on the reaction conditions and product appear upwardly in countercurrent relationship to downwardly 7 below in Table l.

, TABLE 1 Run No. 1 2 3 4 5 6 Temperature, F. 750 e 750 825 825 750 825 Pressure, psig. 1800 1800 .1800 1800 1800 1800 Space vel.,v/v/hr 1.0 1.0 1.0 1.0 1.0 1.0 H, rate. SCFB 7100 7100 7100 7100 7100 7100 Pressuring gas,

14,. mol. 100 99.5 100 99.5 95.0 95.0 C0, mol. 0.5 0.5 5.0 5.0 Product Yield; wt. 93 99 72 70 99 74 Kin. Vis., cs.

l00F. 85.68 79.74 43.23 1 29.66 78.04 28.18 210F. 8.53 8.19 6.27 4.85 8.l5 4.75 Viscosity Index 71 72 81 90 74 94 flowing oil. ln a preferred embodiment, the reactant From th above, it is apparent that under the milder stream, both gas and oil is passed downwardly through conditions the presence of carbon monoxide led to a fixed bed of catalyst extrudates, pellets or spheres. higher yields as compared to runs in which carbon lt is known that under certain conditions the presmonoxide was absent. At the higher temperatures the ence of carbon monoxide in a hydrocracking system inclusion of carbon monoxide afforded a product of has a detrimental effect on the cracking activity of the higher viscosity index than was obtained in its absence. catalyst. However, this phenomenon was presumed to 1 be present only with catalysts containing halogen and EXAMPLE ii that CO had no efi'ect on catalysts which did not con- I v v tain h g FOP p r 3,531,396 This example shows the effect of the presence of cardiSClOSCS that the hydrocracking catalyst which conbon monoxide on the hydrocracking response of a detains no halogen is not appreciably affected by the preswaxed distillate using a cobalt molybdate catalyst hav ence of hydrogen containing as much as 10 percent ing a silica-alumina support. It also shows the residual CO. Surprisingly, it has been found that in the hydroeffect of carbon monoxide. gen treatment of lubricating oils using catalysts free of The same charge as used in Example I a hydrohalogen, the presence of carbon monoxide does have k d b b i passed i h h d h h a fixed an effect on the reaction. AS result Of OBI invention, bed of cobalt mglybdatc catalyst containing 2 8 w{ it is now possible to obtain the same effect as would be t b lt, 10 7 wt percent l bd 33 obtained by severe hydrogenation as by hydrocracking percent silica and the balance alumina. lnall, six runs while obtaining substantially the same yield as would be were made, three at a temperature of 7SOF and three obtained y hydrofming. This was particularly surprisat a temperature of 825F. Runs 1 and 2 show the activing in view of the. prior art which indicated that in e ity of the catalyst under standard CO-free operating hydroc'racking 0f gas oils and the like, the activity of conditions, In Runs 3 and 4 the hydrogen contained Q5 halogen-containing catalysts was suppressed and the mol percent CO. Runs 5 and 6 in which CO-free hydroactivity of halogen-free catalysts was not affected by gen was used show the residual effect of CO. in both the presence of CO. I temperature ranges the highest Vl product was ob- Under a given setof conditions, lubricating oilsof tained when the hydrogen included carbon monoxide. higher quality, as measured by the viscosity index, may The residual effect of carbon monoxide can be seen be prepared in the presence of carbon monoxide or if from Runs 5 and 6, the products of which are intermediate in quality between those of Runs 1 and 2 and Runs 3 and 4 in which carbon monoxide was added to the hydrogen. Data on the reaction conditions and product are set forth below.

TABLE 2 Run Nu. I 2 3 4 5 6 Temperature. F. 750 825 750 825 750 825 Pressure, psig I300 I800 I800 I800 I800 1800 Space vcl. v/v/hr. 1.0 1.0 1.0 1.0 1.0 1.0 Hydrogen ru1c,S('l"H 4400 4400 4400 4400 4400 4400 CO in hydrogen, vul.// 0.5 0.5 Product Yield, WI. 71 87 82 80.9 75 85 79.5 Kin. Vise. cs.

100F. 120.8 51.28 70.85 21.78 83.27 30.45 210F. 10.15 6.54 7.68 4.14 8.44 4.93 Viscosity Index 62 82 74 100 73 91 It will be noted from Examples I and II that the product formed in the presence of carbon monoxide has an unexpectedly lower viscosity than the product formed fraction under hydrocracking conditions including a temperature between about 550 and 850F., a pressubstantially the same in both the absence and presence of carbon monoxide but the inclusion of carbon monoxide led to a yield improvement of 27 percent.

We claim: 1. A process for moderating the hydrocracking of a lubricating oil fraction which comprises contacting said sure between about 500 and 5,000 psig, a space velocin its absence since the magnitude of viscosity decrease ity between about 0.1 and 5.0 v/v/hr. and a hydrogen is ordinarily taken as a measure of the extent of crackrateof between about 500 and 10,000 SCFB with a ing. Since it would be expected in view of the discushalogen-free hydrogenation catalyst in the presence of sion above that less cracking would occur in the presb t about 1 d 10 per-cent Carbon mono)- ence of carbon monoxide, it would be expected that the id ba ed on the hydrogen. I p f formed Presence l be of hlgher 2. The process of claim 1 in which the hydrogenation 0 thafl the Product profluced Its b e catalyst comprises a Group VIII metal or compound The residual effect of CO 1n Example 11 indlcates that thereof Us; neednot be added contlnuously but may be 3. The process of claim 2 in which the Group VIII 3 e metal is palladium.

EXAMPLE 111 4. The process of claim 2 in which the Group v111 This example shows the effect of the use of carbon meta] ls mckel' monoxide during the mild hydrogenation of a hydro- T Process of Clam 2 Whch the Group Vm cracked deasphalted residuum using 0.5 wt. percent metal Cobalt palladium on a low sodium zeolite Y containing sup- 6. The process of claim 1 in which the carbon monoxport. ide concentration is between 0.2 and 5.0 mol percent.

TABLE 3 Run No 1 2 3 4 5 6 Temperature, F. 609 605 605 590 592 592 Pressure, psig v 1500 1500 1500 1500 1500 1500 Space vel. v/v/hr. 0.4 0.4 0.4 0.5 0.5 0.5 Hydrogen rate.SCFB 5000 5000 5000 5000 5000 5000 Pressuring Gas Hydrogen, mol. 100 99.5 92.5 100 99.5 92.5 c0, mol. 0.5 7.5 0.5 7.5 Product Yield, wt. 73 100 100 96 101* 100 Kin. Visc., cs.

100F. 46.21 52.65 52.23 54.01 52.33 52.03 210F. 6.69 7.24 7.29 7.18 7.24 7.30 Viscosity Index 107 106 109 100 107 110 accounted for by the addition of hydrogen in the charge. hiisis producls ilcwzixcd to nominal 0'1. pour pninl.

Under the conditions associated with the lower tem- 7. The process of claim 1 in which the lubricating oil perature runs, the inclusion of carbon monoxide imfraction is a raw distillate. proved the viscosity index of the charge about 7 units. 8. The process of claim 1 in which the lubricating 011 Moreover, the yield was about 5 percent higher when fraction is a deasphalted residuum. the hydrogen treatment was conducted in the presence 9. The process of claim 8 in which the lubricatmgoil of carbon monoxide. Under the more severe temperafra tion is a hydrocracked deasphalted residuum. ture conditions, the viscosity index improvement was The Process of claim 1 Whlch the catalyst prises a refractory amorphous inorganic oxide support.

11. The process of claim 10 in which the support comprises a crystalline zeolite having uniform pore openings of between 6 and 13 A and an alkali metal content of less than 4.0 wt. percent. 

2. The process of claim 1 in which the hydrogenation catalyst comprises a Group VIII metal or compound thereof.
 3. The process of claim 2 in which the Group VIII metal is palladium.
 4. The process of claim 2 in which the Group VIII metal is nickel.
 5. The process of claim 2 in which the Group VIII metal is cobalt.
 6. The process of claim 1 in which the carbon monoxide concentration is between 0.2 and 5.0 mol percent.
 7. The process of claim 1 in which the lubricating oil fraction is a raw distillate.
 8. The process of claim 1 in which the lubricating oil fraction is a deasphalted residuum.
 9. The process of claim 8 in which the lubricating oil fraction is a hydrocracked deasphalted residuum.
 10. The process of claim 1 in which the catalyst comprises a refractory amorphous inorganic oxide support.
 11. The process of claim 10 in which the support comprises a crystalline zeolite having uniform pore openings of between 6 and 13 A and an alkali metal content of less than 4.0 wt. percent. 